A set of 5 Small Round Base Inserts from The Deus Ex Machina range for 30mm.
If you want to show your models on a clockwork nightmare, or storming a steampunk world, these are the bases for you.

Designed with a mix of clockwork machinery, tiles and wood, you can either paint them up to look like a working clockwork world or add foliage and sand, then paint rust effects to show an abandoned construction.
Base Inserts are made to work with Dark age style bases, usable for Warmachine, Hordes or similar games. They are designed to sit in the lip of the base.